On the basis of patient reports, as well as clinical studies, there has been a suspicion for some time that some individuals with IBS who clearly did not have celiac disease appeared to be sensitive to or intolerant of gluten-containing food and the term nonceliac gluten sensitivity has been acknowledged by experts in the field.[35,36] That gluten might play a role in IBS-like syndromes is supported by the symptomatic overlap between IBS and celiac disease[3741] as well as the precipitation of their typical symptoms in IBS individuals when exposed, in a blinded fashion, to gluten.[4244]

In one of these studies, gluten-related disturbances in gastrointestinal function were also documented and those IBS individuals harbouring the human leukocyte antigen (HLA) haplotypes associated with celiac disease were more susceptible to the effects of gluten.[44] The pathogenesis of gluten-related (or more correctly, perhaps, wheat-induced) symptoms in IBS and the benefits of a gluten-free diet remain unclear. Although some studies suggest benefits from gluten restriction,[45] other studies found little additive benefit for gluten restriction over and above that conferred by a low FODMAP diet.[46]

The latter finding suggests that it is the fructan component of wheat (a FODMAP) and not gluten that is the guilty party in wheat sensitivity in IBS. Limited results from formal testing of the immune response to gluten in IBS would support a nonimmune basis for nonceliac gluten sensitivity.[47] The role of a gluten-free diet in IBS remains unclear.